The Parvin Building Animal Resources Center Improvement Plan will significantly increase the animal holding capacity for animal models used in breeding and research activities at the Beckman Research Institute of City of Hope (COH/BRI) and will substantially optimize space utilization at the Division of Comparative Medicine within the centralized Animal Resources Center (ARC) animal facility. Over the past decade, COH/BRI has grown both in research staff (25%) and extramural funding (120%) through the direction of a purposeful, strategic plan to increase biomedical research in the areas of novel therapeutics for catastrophic diseases- mainly cancer and diabetes. This increase in funding has been accompanied by an increase in the number of IACUC-approved animal use protocols (from 118 to 230), and the average daily animal census has increased more than five-fold. As a result, the ARC has recently reached its functional operational capacity, and is facing a critical juncture, challenged with providing enough space and enhanced services to meet the current needs of animal-based research programs (short-term), as well as to plan for continued growth (long-term). COH/BRI has identified animal facility improvement and expansion as a strategic necessity, and is in the process of designing an expansion to the facility. Although the institution has moved forward with minor renovations and equipment acquisition, animal housing currently available is only able to meet current needs, and cannot accommodate new projects or our anticipated future growth in pre-clinical and translational research programs involving animal models. Unless the current ARC animal holding space shortage is addressed, potential disruptions, delays or curtailment of animal model-based research projects may occur. Therefore, the requested space efficient, high density, ventilated rodent housing systems and associated equipment are urgently needed to maintain and further develop our innovative institutional biomedical and translational research programs, while also facilitating new research initiatives, by increasing the animal facility holding capacity and improving operational efficiencies. The requested high density animal housing systems will be used to replace older, less space efficient, ventilated housing systems in two mouse breeding rooms in the animal facility. This will allow the ARC to optimize space utilization in the current facility, and after he facility expansion, while also increasing efficiencies in labor and energy and improving indoor air quality. The requested equipment will support the successful completion of 78 ($23.5M) active and 122 ($35.3M) pending projects involving animal model research, and will help to ensure COH/BRI continues its remarkable history of innovation and achievements in science and medical care.